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The Normal Distribution

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Question 23

The mass of a bag of flour produced at a factory is normally distributed with a mean of 1500 g and a standard deviation of 20 g.

a.

Find the probability of a bag weighing more than 1545 g.

[2]
b.

The quality control manager suspects that the mean mass of the flour bags has changed.

Write down a null and alternative hypothesis for a two-tailed test.

[1]
c.

They take a random sample of 25 bags and find a mean mass of 1512 g.

Test at the 5% significance level whether there is evidence that the mean mass has changed.

[3]
Markscheme

The Normal Distribution Questions

  1. A Level
  2. /Maths
  3. /The Normal Distribution

616 exam-style questions on Edexcel A Level Maths The Normal Distribution, covering 3.1 The Normal Distribution, 3.2 Finding Probabilities for Normal Distributions, 3.3 The Inverse Normal Distribution Function, 3.4 The Standard Normal Distribution, 3.5 Finding the mean and standard deviation, 3.6 Approximating a Binomial Distribution, and 3.7 Hypothesis Testing with the Normal Distribution. Each one has a worked solution and a mark scheme showing where the marks go.

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